Background:Recent basic science research has revealed a decreased tissue expression of peroxisome proliferator-activated receptor (PPAR) γ in lichen planopilaris (LPP). Therefore, thiazolidinediones, being PPARγ agonists, could be used to treat LPP.Methods:We followed 24 patients with LPP who were treated with oral pioglitazone hydrochloride. Improvement in LPP was defined as a decrease in or disappearance of symptoms and perifollicular erythema in the context of halted spread of old patches.Results:Twenty of 24 patients were females. The average age was 52.5 years, and ages ranged from 22 to 70 years. Five of 24 patients have achieved remission; improvement was noted in half of the patients; there was no change in 3 patients; and 4 patients discontinued treatment due to side effects. Side effects were mild and included left calf pain, lightheadedness and nausea, dizziness, and hives.Conclusion:Use of thiazolidinediones might be a new promising venue of LPP treatment.